STING agonists are a new class of drugs for cancer immunotherapy that activate both innate and adaptive antitumor immunity. Recently, multiple clinical trials of STING agonists have been conducted in hematological malignancies and solid tumors. However, STING is commonly suppressed in melanoma through mechanisms that remain unclear. We found that STING expression was epigenetically suppressed by H3K27me3 in melanoma, and EZH2 inhibitor could induce an H3K27 shift from trimethylation to acetylation, resulting in increased expression of STING. Furthermore, a combination of STING agonist and EZH2 inhibitor upregulated major histocompatibility complex class I expression and chemokine production. Whole-transcriptome analysis showed that IFN-1‒related genes were significantly upregulated in the combination treatment group. In addition, the combination treatment synergistically reduced tumor growth and increased CD8 T-cell infiltration in a poorly immunogenic melanoma mouse model B16-F10. These results showed, to our knowledge, a previously unreported mechanism underlying the epigenetic regulation of STING expression in melanoma; a combination of STING agonists and EZH2 inhibitors can boost the antitumor immune response and would be a promising treatment option for patients with melanoma who are refractory to current immunotherapies.
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http://dx.doi.org/10.1016/j.jid.2021.08.437 | DOI Listing |
Cell Rep
January 2025
Smurfit Institute of Genetics, Trinity College Dublin, Dublin 2, Ireland. Electronic address:
Polycomb repressive complex 2 (PRC2), composed of the core subunits EED, SUZ12, and either EZH1 or EZH2, is critical for maintaining cellular identity in multicellular organisms. PRC2 deposits H3K27me3, which is thought to recruit the canonical form of PRC1 (cPRC1) to promote gene repression. Here, we show that EZH1-PRC2 and cPRC1 are the primary Polycomb complexes on target genes in non-dividing, quiescent cells.
View Article and Find Full Text PDFCancers (Basel)
December 2024
Sarcoma Unit, The Royal Marsden Hospital and Institute of Cancer Research, London SW3 6JZ, UK.
There has been noteworthy progress in molecular characterisation and therapeutics in soft tissue sarcomas. Novel agents have gained regulatory approval by the FDA. Examples are the tyrosine kinase inhibitors avapritinib and ripretinib in gastrointestinal stromal tumours (GIST), the immune check point inhibitor atezolizumab in alveolar soft part tissue sarcoma, the γ-secretase inhibitor nirogacestat in desmoid tumours, the NTRK inhibitors larotrectinib and entrectinib in tumours with fusions, the mTOR inhibitor nab-sirolimus in PEComa, and the EZH-2 inhibitor tazemetostat in epithelioid sarcoma.
View Article and Find Full Text PDFTher Adv Med Oncol
January 2025
Department of Molecular Biology of Cancer, Medical University of Lodz, Mazowiecka 6/8, Lodz 92-215, Poland.
The enhancer of zeste homolog 2 (EZH2) is a catalytic component of Polycomb repressive complex 2 (PRC2) mediating the methylation of histone 3 lysine 27 (H3K27me3) and hence the epigenetic repression of target genes, known as canonical function. Growing evidence indicates that EZH2 has non-canonical roles that are exerted as PRC2-dependent and PRC2-independent methylation of non-histone proteins, and methyltransferase-independent interactions of EZH2 with various proteins contributing to gene expression regulation and alterations in the protein stability. is frequently mutated and/or its expression is deregulated in various cancer types.
View Article and Find Full Text PDFLeukemia
January 2025
Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore.
The polycomb protein EZH2 is up-regulated in Chronic Myeloid Leukaemia (CML) and associated with transcriptional reprogramming. Here we tested whether EZH2 might also act as a modulator of the mRNA splicing landscape to elicit its oncogenic function in CML. We treated CML cell lines with EZH2 inhibitors and detected differential splicing of several hundreds of events, potentially caused by the transcriptional regulation of splicing factors.
View Article and Find Full Text PDFMolecules
December 2024
Department of Experimental Medicine, Sapienza University of Rome, 00161 Rome, Italy.
Enhancer of zeste homolog 2 (EZH2) is a methyltransferase involved in cell cycle regulation, cell differentiation, and cell death and plays a role in modulating the immune response. Although it mainly functions by catalyzing the tri-methylation of H3 histone on K27 (H3K27), to inhibit the transcription of target genes, EZH2 can directly methylate several transcription factors or form complexes with them, regulating their functions. EZH2 expression/activity is often dysregulated in cancer, contributing to carcinogenesis and immune escape, thereby representing an important target in anti-cancer therapy.
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